docs: def retire(did):
      """Retire metadata of an asset
      ---
      tags:
        - ddo
      parameters:
        - name: did
          in: path
          description: DID of the asset.
          required: true
          type: string
      responses:
        200:
          description: successfully deleted
        404:
          description: This asset DID is not in OceanDB
        500:
          description: Error
      """
      try:
          if dao.get(did) is None:
              return 'This asset DID is not in OceanDB', 404
          else:
              dao.delete(did)
              return 'Succesfully deleted', 200
      except Exception as err:
          return f'Some error: {str(err)}', 500